diff options
Diffstat (limited to 'kernel/drivers/iio/pressure/bmp280.c')
| -rw-r--r-- | kernel/drivers/iio/pressure/bmp280.c | 416 |
1 files changed, 416 insertions, 0 deletions
diff --git a/kernel/drivers/iio/pressure/bmp280.c b/kernel/drivers/iio/pressure/bmp280.c new file mode 100644 index 000000000..a2602d8dd --- /dev/null +++ b/kernel/drivers/iio/pressure/bmp280.c @@ -0,0 +1,416 @@ +/* + * Copyright (c) 2014 Intel Corporation + * + * Driver for Bosch Sensortec BMP280 digital pressure sensor. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#define pr_fmt(fmt) "bmp280: " fmt + +#include <linux/module.h> +#include <linux/i2c.h> +#include <linux/acpi.h> +#include <linux/regmap.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +#define BMP280_REG_TEMP_XLSB 0xFC +#define BMP280_REG_TEMP_LSB 0xFB +#define BMP280_REG_TEMP_MSB 0xFA +#define BMP280_REG_PRESS_XLSB 0xF9 +#define BMP280_REG_PRESS_LSB 0xF8 +#define BMP280_REG_PRESS_MSB 0xF7 + +#define BMP280_REG_CONFIG 0xF5 +#define BMP280_REG_CTRL_MEAS 0xF4 +#define BMP280_REG_STATUS 0xF3 +#define BMP280_REG_RESET 0xE0 +#define BMP280_REG_ID 0xD0 + +#define BMP280_REG_COMP_TEMP_START 0x88 +#define BMP280_COMP_TEMP_REG_COUNT 6 + +#define BMP280_REG_COMP_PRESS_START 0x8E +#define BMP280_COMP_PRESS_REG_COUNT 18 + +#define BMP280_FILTER_MASK (BIT(4) | BIT(3) | BIT(2)) +#define BMP280_FILTER_OFF 0 +#define BMP280_FILTER_2X BIT(2) +#define BMP280_FILTER_4X BIT(3) +#define BMP280_FILTER_8X (BIT(3) | BIT(2)) +#define BMP280_FILTER_16X BIT(4) + +#define BMP280_OSRS_TEMP_MASK (BIT(7) | BIT(6) | BIT(5)) +#define BMP280_OSRS_TEMP_SKIP 0 +#define BMP280_OSRS_TEMP_1X BIT(5) +#define BMP280_OSRS_TEMP_2X BIT(6) +#define BMP280_OSRS_TEMP_4X (BIT(6) | BIT(5)) +#define BMP280_OSRS_TEMP_8X BIT(7) +#define BMP280_OSRS_TEMP_16X (BIT(7) | BIT(5)) + +#define BMP280_OSRS_PRESS_MASK (BIT(4) | BIT(3) | BIT(2)) +#define BMP280_OSRS_PRESS_SKIP 0 +#define BMP280_OSRS_PRESS_1X BIT(2) +#define BMP280_OSRS_PRESS_2X BIT(3) +#define BMP280_OSRS_PRESS_4X (BIT(3) | BIT(2)) +#define BMP280_OSRS_PRESS_8X BIT(4) +#define BMP280_OSRS_PRESS_16X (BIT(4) | BIT(2)) + +#define BMP280_MODE_MASK (BIT(1) | BIT(0)) +#define BMP280_MODE_SLEEP 0 +#define BMP280_MODE_FORCED BIT(0) +#define BMP280_MODE_NORMAL (BIT(1) | BIT(0)) + +#define BMP280_CHIP_ID 0x58 +#define BMP280_SOFT_RESET_VAL 0xB6 + +struct bmp280_data { + struct i2c_client *client; + struct mutex lock; + struct regmap *regmap; + + /* + * Carryover value from temperature conversion, used in pressure + * calculation. + */ + s32 t_fine; +}; + +/* + * These enums are used for indexing into the array of compensation + * parameters. + */ +enum { T1, T2, T3 }; +enum { P1, P2, P3, P4, P5, P6, P7, P8, P9 }; + +static const struct iio_chan_spec bmp280_channels[] = { + { + .type = IIO_PRESSURE, + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), + }, + { + .type = IIO_TEMP, + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), + }, +}; + +static bool bmp280_is_writeable_reg(struct device *dev, unsigned int reg) +{ + switch (reg) { + case BMP280_REG_CONFIG: + case BMP280_REG_CTRL_MEAS: + case BMP280_REG_RESET: + return true; + default: + return false; + }; +} + +static bool bmp280_is_volatile_reg(struct device *dev, unsigned int reg) +{ + switch (reg) { + case BMP280_REG_TEMP_XLSB: + case BMP280_REG_TEMP_LSB: + case BMP280_REG_TEMP_MSB: + case BMP280_REG_PRESS_XLSB: + case BMP280_REG_PRESS_LSB: + case BMP280_REG_PRESS_MSB: + case BMP280_REG_STATUS: + return true; + default: + return false; + } +} + +static const struct regmap_config bmp280_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + + .max_register = BMP280_REG_TEMP_XLSB, + .cache_type = REGCACHE_RBTREE, + + .writeable_reg = bmp280_is_writeable_reg, + .volatile_reg = bmp280_is_volatile_reg, +}; + +/* + * Returns temperature in DegC, resolution is 0.01 DegC. Output value of + * "5123" equals 51.23 DegC. t_fine carries fine temperature as global + * value. + * + * Taken from datasheet, Section 3.11.3, "Compensation formula". + */ +static s32 bmp280_compensate_temp(struct bmp280_data *data, + s32 adc_temp) +{ + int ret; + s32 var1, var2; + __le16 buf[BMP280_COMP_TEMP_REG_COUNT / 2]; + + ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_TEMP_START, + buf, BMP280_COMP_TEMP_REG_COUNT); + if (ret < 0) { + dev_err(&data->client->dev, + "failed to read temperature calibration parameters\n"); + return ret; + } + + /* + * The double casts are necessary because le16_to_cpu returns an + * unsigned 16-bit value. Casting that value directly to a + * signed 32-bit will not do proper sign extension. + * + * Conversely, T1 and P1 are unsigned values, so they can be + * cast straight to the larger type. + */ + var1 = (((adc_temp >> 3) - ((s32)le16_to_cpu(buf[T1]) << 1)) * + ((s32)(s16)le16_to_cpu(buf[T2]))) >> 11; + var2 = (((((adc_temp >> 4) - ((s32)le16_to_cpu(buf[T1]))) * + ((adc_temp >> 4) - ((s32)le16_to_cpu(buf[T1])))) >> 12) * + ((s32)(s16)le16_to_cpu(buf[T3]))) >> 14; + data->t_fine = var1 + var2; + + return (data->t_fine * 5 + 128) >> 8; +} + +/* + * Returns pressure in Pa as unsigned 32 bit integer in Q24.8 format (24 + * integer bits and 8 fractional bits). Output value of "24674867" + * represents 24674867/256 = 96386.2 Pa = 963.862 hPa + * + * Taken from datasheet, Section 3.11.3, "Compensation formula". + */ +static u32 bmp280_compensate_press(struct bmp280_data *data, + s32 adc_press) +{ + int ret; + s64 var1, var2, p; + __le16 buf[BMP280_COMP_PRESS_REG_COUNT / 2]; + + ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_PRESS_START, + buf, BMP280_COMP_PRESS_REG_COUNT); + if (ret < 0) { + dev_err(&data->client->dev, + "failed to read pressure calibration parameters\n"); + return ret; + } + + var1 = ((s64)data->t_fine) - 128000; + var2 = var1 * var1 * (s64)(s16)le16_to_cpu(buf[P6]); + var2 += (var1 * (s64)(s16)le16_to_cpu(buf[P5])) << 17; + var2 += ((s64)(s16)le16_to_cpu(buf[P4])) << 35; + var1 = ((var1 * var1 * (s64)(s16)le16_to_cpu(buf[P3])) >> 8) + + ((var1 * (s64)(s16)le16_to_cpu(buf[P2])) << 12); + var1 = ((((s64)1) << 47) + var1) * ((s64)le16_to_cpu(buf[P1])) >> 33; + + if (var1 == 0) + return 0; + + p = ((((s64)1048576 - adc_press) << 31) - var2) * 3125; + p = div64_s64(p, var1); + var1 = (((s64)(s16)le16_to_cpu(buf[P9])) * (p >> 13) * (p >> 13)) >> 25; + var2 = (((s64)(s16)le16_to_cpu(buf[P8])) * p) >> 19; + p = ((p + var1 + var2) >> 8) + (((s64)(s16)le16_to_cpu(buf[P7])) << 4); + + return (u32)p; +} + +static int bmp280_read_temp(struct bmp280_data *data, + int *val) +{ + int ret; + __be32 tmp = 0; + s32 adc_temp, comp_temp; + + ret = regmap_bulk_read(data->regmap, BMP280_REG_TEMP_MSB, + (u8 *) &tmp, 3); + if (ret < 0) { + dev_err(&data->client->dev, "failed to read temperature\n"); + return ret; + } + + adc_temp = be32_to_cpu(tmp) >> 12; + comp_temp = bmp280_compensate_temp(data, adc_temp); + + /* + * val might be NULL if we're called by the read_press routine, + * who only cares about the carry over t_fine value. + */ + if (val) { + *val = comp_temp * 10; + return IIO_VAL_INT; + } + + return 0; +} + +static int bmp280_read_press(struct bmp280_data *data, + int *val, int *val2) +{ + int ret; + __be32 tmp = 0; + s32 adc_press; + u32 comp_press; + + /* Read and compensate temperature so we get a reading of t_fine. */ + ret = bmp280_read_temp(data, NULL); + if (ret < 0) + return ret; + + ret = regmap_bulk_read(data->regmap, BMP280_REG_PRESS_MSB, + (u8 *) &tmp, 3); + if (ret < 0) { + dev_err(&data->client->dev, "failed to read pressure\n"); + return ret; + } + + adc_press = be32_to_cpu(tmp) >> 12; + comp_press = bmp280_compensate_press(data, adc_press); + + *val = comp_press; + *val2 = 256000; + + return IIO_VAL_FRACTIONAL; +} + +static int bmp280_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + int ret; + struct bmp280_data *data = iio_priv(indio_dev); + + mutex_lock(&data->lock); + + switch (mask) { + case IIO_CHAN_INFO_PROCESSED: + switch (chan->type) { + case IIO_PRESSURE: + ret = bmp280_read_press(data, val, val2); + break; + case IIO_TEMP: + ret = bmp280_read_temp(data, val); + break; + default: + ret = -EINVAL; + break; + } + break; + default: + ret = -EINVAL; + break; + } + + mutex_unlock(&data->lock); + + return ret; +} + +static const struct iio_info bmp280_info = { + .driver_module = THIS_MODULE, + .read_raw = &bmp280_read_raw, +}; + +static int bmp280_chip_init(struct bmp280_data *data) +{ + int ret; + + ret = regmap_update_bits(data->regmap, BMP280_REG_CTRL_MEAS, + BMP280_OSRS_TEMP_MASK | + BMP280_OSRS_PRESS_MASK | + BMP280_MODE_MASK, + BMP280_OSRS_TEMP_2X | + BMP280_OSRS_PRESS_16X | + BMP280_MODE_NORMAL); + if (ret < 0) { + dev_err(&data->client->dev, + "failed to write ctrl_meas register\n"); + return ret; + } + + ret = regmap_update_bits(data->regmap, BMP280_REG_CONFIG, + BMP280_FILTER_MASK, + BMP280_FILTER_4X); + if (ret < 0) { + dev_err(&data->client->dev, + "failed to write config register\n"); + return ret; + } + + return ret; +} + +static int bmp280_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + int ret; + struct iio_dev *indio_dev; + struct bmp280_data *data; + unsigned int chip_id; + + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + + data = iio_priv(indio_dev); + mutex_init(&data->lock); + data->client = client; + + indio_dev->dev.parent = &client->dev; + indio_dev->name = id->name; + indio_dev->channels = bmp280_channels; + indio_dev->num_channels = ARRAY_SIZE(bmp280_channels); + indio_dev->info = &bmp280_info; + indio_dev->modes = INDIO_DIRECT_MODE; + + data->regmap = devm_regmap_init_i2c(client, &bmp280_regmap_config); + if (IS_ERR(data->regmap)) { + dev_err(&client->dev, "failed to allocate register map\n"); + return PTR_ERR(data->regmap); + } + + ret = regmap_read(data->regmap, BMP280_REG_ID, &chip_id); + if (ret < 0) + return ret; + if (chip_id != BMP280_CHIP_ID) { + dev_err(&client->dev, "bad chip id. expected %x got %x\n", + BMP280_CHIP_ID, chip_id); + return -EINVAL; + } + + ret = bmp280_chip_init(data); + if (ret < 0) + return ret; + + return devm_iio_device_register(&client->dev, indio_dev); +} + +static const struct acpi_device_id bmp280_acpi_match[] = { + {"BMP0280", 0}, + { }, +}; +MODULE_DEVICE_TABLE(acpi, bmp280_acpi_match); + +static const struct i2c_device_id bmp280_id[] = { + {"bmp280", 0}, + { }, +}; +MODULE_DEVICE_TABLE(i2c, bmp280_id); + +static struct i2c_driver bmp280_driver = { + .driver = { + .name = "bmp280", + .acpi_match_table = ACPI_PTR(bmp280_acpi_match), + }, + .probe = bmp280_probe, + .id_table = bmp280_id, +}; +module_i2c_driver(bmp280_driver); + +MODULE_AUTHOR("Vlad Dogaru <vlad.dogaru@intel.com>"); +MODULE_DESCRIPTION("Driver for Bosch Sensortec BMP280 pressure and temperature sensor"); +MODULE_LICENSE("GPL v2"); |